In one NCIS scene, a 3D hologram identifies a person’s teeth, precisely matching the killer’s bite to a bite mark on a victim. “A little 3D magic for clarity and I give you—the killer’s incisors!” NCIS character “Abby” announces proudly.

John Stossel loves crazy Abby, but notes that in the real world, court-approved experts reach similar conclusions—without good science to back them up.

Alfred Swinton was convicted of murder after “bite mark expert” Dr. Gus Karazulas said Swinton’s teeth matched a bite on a victim.

Karazulas told the TV show Cold Case Files: “We look at the evidence and we make sure that if we are going to make a decision it’s gonna be a truthful decision.”

But a decade later, DNA testing showed it was not Swinton’s DNA on the bite mark. He was released after 18 years in prison.